1. Field
The present invention relates to a three-dimensional (3D) image display device.
2. Description of the Related Art
With the development of information technology, the market of display devices, which are the connection media between a user and information, are growing. Thus, display devices, such as a Liquid Crystal Display (LCD), an Organic Light Emitting-Diode Display (OLED), an Electrophoretic Display (EPD), a Plasma Display Panel (PDP), and the like, have been increasingly used.
Some of the above-described display devices are implemented as a three-dimensional (3D) image display device. 3D image display devices are classified into a stereoscopic technique and an autosteroscopic technique.
The stereoscopic technique uses parallax images of left and right eyes that have a large 3D effect. The stereoscopic technique is divided into a glasses method and a glasses-free method, both of which have been put to practical use.
In the related art, the glasses-free method changes a light path by using a fixed lens array such as a lenticular sheet. However, this method has a disadvantage in that it is impossible to switch between a two-dimensional (2D) image and a 3D image. For solving the disadvantage, glasses-free methods capable of switching between a 2D image and a 3D image, such as a liquid crystal filing method, a liquid crystal lens method, and a polarizing lens method, have been researched and commercialized.
However, when the liquid crystal filing method, the liquid crystal lens method, or the polarizing lens method is applied to a display device that does not emit a polarization light source, a double structure needs to be employed or a particular structure needs to be added to the display device, and thus a single 3D optical system cannot be employed. Therefore, improvements of the methods are required.